Sunday, August 11, 2013

Propolis acts primarily as a biocide against invasive
bacteria and fungi in the hive, suggesting its potential for industrial
applications. In food application, propolis is considered as a chemical
preservative in meat products, extending shelf life of frozen meat and other
food. The mechanism of action is still unclear due to the synergy of multiple
compounds contained in propolis and due to parallel targeting of multiple
pathways within each affected organism. Here, we examined the antimicrobial
properties of dimethylsulfoxide (DMSO) Czech propolis extract. Until recently,
DMSO was only rarely used in the propolis studies, although the other solvents
tested (mostly ethanol) may significantly affect the observed inhibitory
effects, notwithstanding the antimicrobial effects of ethanol itself. Here, we
provide results of zone inhibition tests against Aspergillus fumigatus,
Microsporum gypseum, Microsporum canis, Candida albicans, Escherichia coli,
Staphylococcus aureus, Listeria monocytogenes, and Enterococcus faecalis.

Although we determined inhibitory effects against all the
microorganisms tested, the dose-dependent response curves were not similar to
each other. While inhibitory effects against C. albicans or S. aureus were
strictly dose-dependent, responses of M. gypseum and E. faecalis displayed
plateau across the broad range of concentrations tested. Interestingly,
response of E. coli revealed the double-peak dose-dependent curve, and
responses of M. canis and L. monocytogenes decreased at the highest
concentrations tested. Suggested is evaluation of DMSO propolis extracts in
experimental treatment of human and veterinary infections, preferably in
multitherapy with antibiotics.